Process of preserving yeast



Patented Feb. 23, 1926.

UNITED STATES PATENT OFFICE.

LUDOLF IJNDEMAIN'N, OF ALTONA-BAHBENFELD, GERMANY, ASSIGNOR TO '1. P.

' HODGE, OF PARK RIDGE,- ILLINOIS.

PROCESS OF I PRESERVING YEAST.

No Drawing To all 'wlwm it concern.

Be it known that'I, LU'DOLF LINDEMQANN, a citizen of the German Republic, residing in Altona-Bahrenfeld, Germany, have in vent-ed certain new and useful Processes of Preserving Yeast; and I do hereby declare the following to be a full, clear, and exact description of the invention, of which the following is a specification.

- It is well known in the prior art that fresh yeast is washed in lar e quantities of water in order to remove t e particles of dirt contained therein and that in carrying out this washing process cold water has been employed of as low a temgerature as possible. Yeast when obtained 0m molasses and washed in, such a manner will, after a period of 24 hours, develop a brown rim and send forth a sour smell and yeast ob;

tained from corn often assumes a blueish-' grey colour and will not keep for any length the blueish-grey colour of the corn-yeast will not be produced, and the yeast, increases its lasting capacity by weeks, in-

creasing at the Sametime its germinating power. Y o 1 l'Vholly apart from the question of washing at low temperatures, it is 'a well known fact that glycogen in yeast will be caused to ferment at'highe'r temperatures, that is to say at temperatures of more than 25 degrees centigrade, and this will take-place tea still greater extent when air is ad mitted to the yeast. This is the causeof "the molasses-yeast forming very rapidly the dirty brown and of the porn-yeast as- Application filed August 3. 1923. Serial No. 655,524.

suming the blueish-grey colour when the yeast. is stored in a warm place which fre quently cannot be avoided.

By the use of this invention these difiiculties can be wholly avoided in manufacturing bywashing the finely distributed, usually but not necessarily fresh yeast in sufiicient quantities of warm water of at least 83 degrees and at the utmost of 43 degrees centigrade for a sufficient length of'time until with the aid of the iodine or other conventional test it can then be proved, that the amount of glycogen contained in the yeast has considerably decreased. It is still better practice. to carry out the process until glycogen disappears altogether.

According to a great number of experiments made, the addition of sugar or sugarcontaining substances tothe wash waterin conjunction with the heat will cause the yeast to give off its glycogen more rapidly than where plain water is used. Yeast prepared in such a manner can even be sent to the tropics without changing its appearance or decreasing its germinating power.

After the removal of the glycogen, the finely distributed yeast is prepared for marnet in conventional manner.

I claim as my-invention: l. The herein described method of making fresh yeast lasting consisting in washing finely distributed fresh yeast in water of from thirty-three to forty-three degrees centi ade until tests show the substantial to r-nmpete removal of glycogen.

2. The herein described method of making fresh yeast lasting consisting in washing finely distributed fresh yeast in water containing sugar substances of from thirtylhree to forty-three degrees centigrade until tests show the substantial to complete removal of glycogen.

' LUDOLF LINDEMANN. 

